1. Field of the Invention
The present invention relates to in-vehicle cameras capable of suppressing the influence of noise generated therein.
2. Description of the Related Art
A patent document 1, Japanese patent laid open publication No. 2003-51350, discloses a conventional technique for connecting an electronic circuit board (or a printed circuit board) with a cable harness (which is also known as a wire harness). The electronic circuit board forms a vehicle electronic unit composed of a plurality of electronic circuit boards which are connected together through cables.
The conventional technique for connecting an electronic circuit board with a cable harness previously described is applied to an in-vehicle camera which is arranged at the inside of a windshield glass of a vehicle, for example. Specifically, such an in-vehicle camera has an imager board and a controller board.
Imagers are mounted on the imager board. The imagers receive incident light for producing front view images, convert the received incident light to image data, and generate and transmit image signals. A control circuit is mounted on the controller board, which receives the image signals transmitted from the imager board and performs an image processing on the received image signals.
In general, the imager board is arranged in an approximately vertical direction, which is perpendicular to a horizontal direction, in view of lenses in the imagers mounted on the imager board. On the other hand, the controller board having the control circuit is arranged in a direction which is approximately equal to the horizontal direction in order for the driver of the vehicle to have a clear field of view.
A casing is composed of an upper-side casing and a lower-side casing. The imager board and the controller board are assembled with the casing so that the casing accommodates the imager board and the controller board, and one surface of each of the imager board and the controller board is covered with the upper-side casing of the casing. The imager board and the controller board are electrically connected together through cables arranged on the other surface thereof which is not covered with the upper-side casing. The cables are fixed on the surface of each of the imager board and the controller board and covered with the lower-side casing.
Because this type of the in-vehicle camera performs high-speed data transmission of image signals from the imager board having the imagers to the controller board having the control circuit, the cables often generate noise. Because the lower-side casing is arranged close to each of the imager board and the controller board, noise generated in the cables is easily propagated to the outside of the casing. Recently, because a radio device, etc. is arranged near the in-vehicle camera, there is a strong demand to suppress noise generated by the in-vehicle camera of a vehicle.